2of 5Protesters gather at San Francisco International Airport to denounce President Donald Trump's executive order that bars citizens of seven predominantly Muslim countries from entering the U.S. Saturday, Jan. 28, 2017, in San Francisco.Photo: Marcio Jose Sanchez, AP

3of 5Protesters gather at O'Hare International Airport after people were detained, including green card holders, Saturday, Jan. 28, 2017, in Chicago. They were detained following President Donald Trump's executive order on Friday that bans legal U.S. residents and visa-holders from seven Muslim-majority nations from entering the U.S. for 90 days and puts an indefinite hold on a program resettling Syrian refugees. (Chris Sweda/Chicago Tribune via AP)Photo: Chris Sweda, AP

4of 5Protesters gather at O'Hare International Airport after more than a dozen were detained, including green card holders, Saturday, Jan. 28, 2017, in Chicago. They were detained following President Donald Trump's executive order on Friday that bans legal U.S. residents and visa-holders from seven Muslim-majority nations from entering the U.S. for 90 days and puts an indefinite hold on a program resettling Syrian refugees. (Chris Sweda/Chicago Tribune via AP)Photo: Chris Sweda, AP

5of 5Protesters gather at O'Hare International Airport after more than a dozen people were detained, including green card holders, Saturday, Jan. 28, 2017, in Chicago. They were detained following President Donald Trump's executive order on Friday that bans legal U.S. residents and visa-holders from seven Muslim-majority nations from entering the U.S. for 90 days and puts an indefinite hold on a program resettling Syrian refugees. (Chris Sweda/Chicago Tribune via AP)Photo: Chris Sweda, AP

The Trump administration showed no sign early Sunday of backing down from an executive order that bans entry to the United States by refugees, migrants and even green-card holders from seven mostly Muslim countries.

Despite judicial rulings in several cities across the country overnight that immediately blocked enforcement of the ban to varying degrees, the Department of Homeland Security said in a statement early Sunday that it would continue to implement President Donald Trump's action.

The statement said simultaneously that the administration "will comply with judicial orders" and that the order remained in place.

"Prohibited travel will remain prohibited, and the U.S. government retains its right to revoke visas at any time if required for national security or public safety," the statement said. "No foreign national in a foreign land, without ties to the United States, has any unfettered right to demand entry into the United States or to demand immigration benefits in the United States."

Just after 8 a.m. ET Sunday, Trump tweeted: "Our country needs strong borders and extreme vetting, NOW. Look what is happening all over Europe and, indeed, the world - a horrible mess!"

The Department of Homeland Security noted that "less than one percent" of international air travelers arriving Saturday in the United States were "inconvenienced" by the executive order - though the situation described by lawyers and immigrant advocates across the country Saturday was one of widespread confusion and even chaos at airports where travelers from the targeted countries were suddenly detained.

The virtually unprecedented action does not apply only to migrants, refugees and U.S. legal residents - green-card holders - from Iraq, Iran, Sudan, Somalia, Syria, Libya and Yemen; those subject to being denied entry include dual nationals or people born in one of the seven countries who hold passports even from U.S. allies, such as the United Kingdom.

Federal courts began stepping in as requests for stays of Trump's actions were sought.

Late Saturday, a federal judge in New York temporarily blocked deportations nationwide. Her ruling was followed by similar decisions by federal judges in Virginia, Seattle and Boston.

In Brooklyn, Judge Ann Donnelly of the U.S. District Court granted a request from the American Civil Liberties Union to stop the deportations after determining that the risk of detainees being harmed if they were returned to their home countries necessitated the decision.

Next came a temporary restraining order by District Judge Leonie Brinkema in Alexandria, Virginia, who blocked for seven days the removal of any green-card holders detained at Dulles International Airport. Brinkema's action also ordered that lawyers have access to those held there because of the ban.

And just before 2 a.m. Sunday in Boston, two federal judges ruled for two University of Massachusetts Dartmouth associate professors - Iranian nationals who are permanent legal residents in the United States - who were held at Logan International Airport when they landed after travel for an academic conference.

The Boston Globe reported that the judges also imposed a seven-day restraining order on Trump's executive action.

The order triggered harsh reactions from not only Democrats and others who typically advocate for immigrants but also key sectors of the U.S. business community. Leading technology companies recalled scores of overseas employees and sharply criticized the president. Legal experts forecast a wave of litigation over the order, calling it unconstitutional. Lawyers and advocates for immigrants are advising them to seek asylum in Canada.

Yet Trump, who centered his campaign in part on his vow to crack down on illegal immigrants and impose what became known as his "Muslim ban,'' was unbowed. As White House officials insisted that the measure strengthens national security, the president stood squarely behind it.

"It's not a Muslim ban, but we were totally prepared," Trump told reporters Saturday in the Oval Office. "You see it at the airports, you see it all over. It's working out very nicely, and we're going to have a very, very strict ban, and we're going to have extreme vetting, which we should have had in this country for many years."

In New York, Donnelly seemed to have little patience for the government's arguments, which focused on the fact that the two defendants named in the lawsuit had already been released.

Donnelly noted that those detained were suffering mostly from the bad fortune of traveling while the ban went into effect. "Our own government presumably approved their entry to the country," she said at one point, noting that, had it been two days earlier, those detained would have been granted admission without question.

During the hearing, ACLU attorney Lee Gelernt informed the court that he had received word of a deportation to Syria, scheduled within the hour. That prompted Donnelly to ask whether the government could assure that the person would not suffer irreparable harm. Receiving no such assurance, she granted the stay to the broad group included in the ACLU's request.

A senior Department of Homeland Security official said late Saturday that 109 people had been denied entry into the United States. All had been in transit when Trump signed the order, he said, and some had already departed the United States on flights by late Saturday while others were still being detained awaiting flights. Also, 173 people had not been allowed to board U.S.-bound planes at foreign airports.

In the wake of the first two judicial rulings late Saturday, cheers erupted at Dulles Airport in Northern Virginia as a couple emerged from the gray doors blocking the Customs and Border Protection screening area. "Go see the lawyers!" about 150 protesters chanted, directing them toward a throng of volunteer lawyers.

The young woman was teary as she pushed a full luggage cart toward the terminal exit. Another woman, who also was crying, ran up to her. "I'm looking for my parents! They are elderly!"

Javad Fotouha said he is Iranian but has a green card. He said he and his wife had been detained for four hours after landing at Dulles about 6:30 p.m.

He said he and his wife had read on their phones during their layover in Istanbul that Trump had signed the executive order about five hours earlier. "Yes, I was scared," Fotouha said.

At 11:35 p.m., about 80 protesters and lawyers started chanting "Contempt of court!" and "Let them in!" as lawyers said officials were ignoring the federal judge's order requiring that they have access to people being detained.

Fatemeh Ebrahimi, an Iranian who lives in Montgomery County, Maryland, was released at Dulles just before midnight, following a nearly six-hour wait with her two children after their plane landed. She said they traveled to Iran 10 days ago to celebrate birthdays with friends and family.

Ebrahimi said she has a green card, and her children, ages 21 and 7, are U.S. citizens. Her son emerged in a wheelchair with his sister on his lap, saying authorities had given them soup to eat while they waited.

"My kids are so tired right now," a weary-looking Ebrahimi said as she made her way through a thicket of lawyers and reporters toward the terminal doors. "They just kept us waiting."

Shortly after midnight, Sen. Cory Booker, D-N.J., emerged from a Dulles Airport hallway being guarded by police officers near the customs screening area. Speaking to a crowd of more than 100 protesters, Booker said federal officials had told him that the remaining detainees would be released "momentarily."

Volunteer lawyers said one person remained to be released as of 12:30 a.m. The lawyers said others who had been released had told them two additional men had been handcuffed after they refused to give authorities their green cards, and their status was unknown. Lawyers said they still had not been permitted to speak with those being detained - what they called a violation of the federal judge's court order.

Booker told protesters that he agreed with the attorneys and predicted a "long, arduous and tough fight" over the executive order. "This is not a one-night thing, and it's not a one-day thing," he said.

After most protesters and lawyers had gone home for the night, Binto Adan and her two young children, an 8-year-old boy and a 9-year-old girl, emerged at 1:20 a.m. Sunday from the customs screening area. Adan ducked under the ropes lining the walkway and hugged two relatives who were waiting for them.

Adan's daughter had tears in her eyes as her mother led the children toward the terminal exit. Adan did not speak to reporters, but one of her relatives said the family had endured a 17-hour ordeal.

A nephew of Adan's, Najib Abi, said his aunt and her children arrived at Dulles at 8 a.m. Saturday from Kenya. They were supposed to transfer to another flight to live in Minnesota, where her husband was waiting for them. The family is Somali, but the children and their father are U.S. citizens, Abi said. Adan has an I-130 visa for relatives of U.S. citizens, he said.

Abi said immigration officials called his uncle Saturday, saying his wife and children were detained. Abi said his uncle was told that someone would need to retrieve the children by 9:30 a.m. Sunday or they would be sent back to Kenya with their mother.

Abi said he and other relatives arrived at Dulles from Minnesota late Saturday. He said Adan didn't have a cellphone. "We weren't allowed to talk to them," Abi said.

Then, without any explanation, Adan and her children were released.

As of 2 a.m., one Syrian woman was still detained at Dulles, said Mirriam Seddiq, a volunteer lawyer. Attorneys were told that the woman would be held overnight and would have an initial asylum hearing Sunday morning, Seddiq said.

The woman arrived at Dulles at 7 p.m. Saturday with a nonimmigrant J2 visa, Seddiq said. Her husband is in the United States on a J1 visa for professional training, Seddiq said.

Several lawyers would spend the night at Dulles, Seddiq said, with more returning Sunday morning to try to get access to any international passengers detained.

A Customs and Border Protection official at Dulles told lawyers that they were awaiting directions from the Department of Homeland Security's counsel office, Seddiq said.

Jerry Markon covers the Department of Homeland Security for the Post's National Desk. He also serves as lead Web and newspaper writer for major breaking national news.

Katherine Shaver is a transportation and development reporter. She joined The Washington Post in 1997 and has covered crime, courts, education and local government but most prefers writing about how people get — or don't get — around the Washington region.